1. Field of the Invention
The present invention relates to a perpendicular magnetic recording medium in general employed in a magnetic recording medium drive such as a hard disk drive (HDD), for example.
2. Description of the Prior Art
A perpendicular magnetic recording medium is well known in the technical field of magnetic recording media such as hard disks. A soft magnetic underlayer is incorporated in the perpendicular magnetic recording medium. The underlayer is designed to receive a magnetic recording layer on a substrate. The underlayer is supposed to realize enlargement of the magnetization in the magnetic recording layer in the vertical direction perpendicular to the surface of the substrate when a magnetic field is applied from a so-called single-pole head. In fact, it is revealed that the underlayer is not effective to reinforce the magnetization in the magnetic recording layer in the vertical direction as expected.